buildsomething wrote:Something still doesn't make sense here. A smaller pulley does not increase resolution unless it works in conjuction with another pulley that is much larger. If the driver and driven are the same diam, no matter how small or how fine the pitch that is used, the resolution is still the same.

In my cutting laser I have a 3:1 reduction from stepper to the driven ass'y. This reduces my speed by 3X, increase my torque available by 3X and increases the resolution by 3X. In my case, I didn't need speed. I can move my 5lb gantry at speeds over 800 ipm which is way way to fast anyway for cutting.

Richard

In my simple system the motor is driving the pulley which drives the belt attached to the moving part. So all I care about is diameter of the pulley on the motor. It is actually calculated in teeth, so the fewer teeth per rev (smaller dia.), the higher the resolution.

I have all the changes ready and I programmed the router in Aspire. I have some Acrylic coming tomorrow (hopefully) and I will cut the parts. They nested pretty well. and won't take up too much material. It should take about 40 minutes to cut. I could easily optimize it to take a lot less time, but it is not worth it for one job..

I will use my CNC router. It is just easier at this point and can fit the full raw stock without cutting down. Ideally this would be lasered so a laser can make a complete set of parts for a new machine. I have a couple stepped areas where bearings drop in. That would need a slight change. Other than that, it looks good for a laser.

I will use a 1/16 solid carbide end mill from Precise Bits. I bought a couple of these a few years ago and they seem to last forever. I must have cut 100's of parts on them and I have yet to retire one. I have even cut some 6061 aluminum with them. I also have a 0.010 end mill that I use to mill PCBs.

I love the work you've done on this project. I would really like to build a laser cutter for just doing cutting, no etching right now. Are you planning on releasing a "final" drawing of all the laser cut parts for laser cutting? I don't have access to a CNC router or laser cutter right now so I will probably just have them cut at Pololu or Ponoko. I'll also probably have a bunch of questions for you once I get farther into the build. Thanks for any help you can give.

I have a drawing done, but I want to do a test cut on my router. Unfortunately the material did not arrive until today. I might be able to cut tonight. If the parts workout and the cut time is not too long, I may run an extra set or two later in the week.

Have you thought about attempting to add a vacuum assist to your machine or have you found it unnecessary so far? It seems like it would be fairly easy to build a vacuum box to go on your Z platform. Have you had any problems when cutting with parts moving or are the cutting speeds slow enough to not get any movement on the parts?

A vacuum or downdraft system would be a great additon to any laser cutter for a lot of reasons, but not really a necessity. The laser cutting/engraving action does not affect the workpiece much. It does a good job of handling the smoke and keeps small pieces from flying around.

On my system the thing that affectes the work is the mostly the flushing fan and to a lesser extent the assist air. I could easily cut a playing card just by setting it down. If I were to try to cut a small piece of regular paper, it would probably move. Thin paper often tends to curl while cutting and small cutout pieces can blow around.